My car's (83 GSL) OEM alternator siezed on me about a month ago. Yesterday, I finally finished putting the new one in, along with a new belt. Plugged in the connector on the back, then bolted down the metal tab.

Today it was thunderstorming. I had to run some errands, and trusted the car enough to take it out. Seemed to be working pretty well - wipers seemed slow and the gauges seemed dim, but I hadn't driven it in over a month so I thought nothing of it. Got to where I was going, parked it, and did my ****.

Come back out, get in, pull away...at a stoplight, I notice my tach jumping randomly from idle to 1500-2000 RPM very quickly and erratically. I can feel and hear that the engine isn't revving; must be electrical. Uh-oh.

10 miles down the road battery gauge is reading 10V; have to turn off my radio and lights to keep the wipers working right.

Come after that gauge drops to around 8V and I force my window down so I can ******* see in front of me. No lights, no wipers, no heat. Just trying to keep it running.

I just got it home. Belt is still on there, everything's plugged in. What in god's name is wrong? This is a reman OEM alternator from Checker with a limited lifetime warranty. All my connections seem to be good.

 

Sounds like you ran, the whole trip just off the battery. You got both cables to the alternator tied down properly?

If so, then get the alternator tested.

And now that you drained the battery, it'll probably never charge up fully again...

 

that suck i had a lot of alt probmes

 

I haven't changed anything from the way they were tied down before. Is there any way to test the alternator in my garage with a multimeter?

 

They can test it at the store. Best bet is to use your multi meter on the alt to see if you are getting anything out of it. Double check to make sure the alt is grounded well, if not you will get nothing out of it. You should also replace the 20 year old wires now.

 

How? Which probe should I touch to what?

 

With the engine running, check the voltage across the battery with a voltmeter red to + black to - terminal. It should read 13 - 14.5 volt range. Less than 13 and its not charging, more than 14.5 and its over charging. You should probably charge the battery fully before the test. It sounds like its not charging.

 

My alternator went bad killing my battery at the same time. I too just changed my alternator not thinking that the battery had problems. Changed alt again and after 20 minutes of driving my tach was acting crazy. My battery was fried. Changed it and all was good. I'd check the battery too. Get it tested.

 

Voltage across the battery with the engine running is high 11's. It's not charging. I need to check the alternator. The question is how.

 

When I buy a battery, I buy the highest cranking amps rated battery I can find that fits, its a little more but worth it. If you buy a cheap battery, this could cause premature failure of the alternator / regulator, it definitely makes the alt and regulator work harder. Just one of the things I never try to go cheap on..

 

start the car and pull off the negative cable of the battery and see if it'll stay running. If it does then the alt should be fine. You can also check the voltage with a tester on the back of the alt where the power feed is (red and white wire)? should be higher voltage there than the battery

 

Positive probe to the feed, negative to a ground right?

 

yes

 

Take it out and to Advance or Autozone, they have a fixture to spin it and check to see if it is charging. If you just replaced the alt wouldnt it still be under warantee?

 

Should be. I'd just like to do my best to **** with it in the comfort of my own home; I don't trust dudes at parts counters at all (ESPECIALLY Auto Zone). The amount of times I've just plain gotten wrong parts is astonishing; I just can't bring myself to trust them.

May have to though

 

I used to do this as well until I read somewhere it can do damage to a known "good" alternator. I have also heard that if you do this on a newer car with a computer that you can damage the computer as well.. not that the 1st gen's have to worry about that.

If its only charging 11 volts, take it back and get them to warantee it.. its bad.

 

Just poked around with the multimeter.

The T-shaped plug that goes into the back of the alternator has 9V or so coming off of each point.

Battery is reading high 11's across.

With the red probe on the alternator pole and the black one grounded I got numbers in the high 9V range.

Seems bad to me. *********...refurbished my ***.

 

I'm only suggesting this to test the alt for the 1st gen 7. Testing the alt this way on Porsches or BMW's.... sets the check engine light on. I don't recommend this test on newer cars.
sounds like the alt is bad.

 

Jumpstarting or even making an alt charge a low battery is very hard on the alternator or could fry a weak alternator..

I agree, the rebuilt starters and alternators, they just replace the bare minimum and sell it as rebuilt.

 

Now that you're on your way to the store, take the battery with you and have it tested too. You're they're so why not?

Try to charge it up first,...

 

Speaking of testing the battery, my friend's FB's alt shorted internally which killed the battery. We had to replace them both. That's why the alt's not painted in this picture.